Metal working



April 16, 1929- J. ROSENBERG METAL WORKI NG Original Filed Jan. 9, 1925Fig. 5

JA mas Rosa/551M INVIEN TOR.

. ATTORNEY.

Patented Apr. 16, 1929.

UNITED STATES PATENT OFFICE.

JAMES ROSENBERG, F CLEVELAND, OHIO, ASSIGNOR TO METAL FORMING PROCESS,

INC., OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

METAL WORKING.

Application filed January 9, 1925, Serial No. 1,450. Renewed July 18,1928.

and surface.

The primary object of the invention is to produce duplicates more exactand accurate in even minute details of surface finish than hasheretofore been accomplished. Another object is to produce suchduplicates in a small fraction of the time heretofore required in theproduction of inferior copies. A further object is to attain theseresults at a minimum of expense. A still further object and advantagemade possible by my invention is the employment to these ends of metalin the form of relatively thin flat pieces which may be easily cut fromcommercially available rolled sheets of metal which have already beenhot or cold worked, acquiring thereby the superiority of greateruniformity and density throughout. It is apparent that these objects arehighly desirable especially in any situation where the first requirementis very great accuracy in detail of reproduction, for example in thereproduction of plates for printing, lithographing, and embossing, inthe production in large quantities of phonograph records from a masterrecord, etc.

I have attained these objects by the use of various alloys ofnon-ferrous metals in a process which, while neither casting norforging, yet somewhat resembles each of these well known operations andmight be considered as lying somewhere between them.

In the drawings:

Fig. 1 represents diagrammatically in partly sectional elevation a pressthe bed of which is equipped with a heating device, and which comprisesthe apparatus employed in carrying out my invention.

Fig. 2 shows figuratively an original or master pattern.

Fig. 3 shows similarly a matrix, pattern or mold.

Fig. 4 shows the duplicate reproduction of the original shown in Fig. 2.

While not entirely comprehensive of my invention, yet as the best meansof disclosing the same, I have chosen as an example illustrative thereofthe object shown in Fig. 2 as the original, the visible or nearest faceof which suppose it is desired to duplicate. Thisobject for simplicityof illustration is provided with only the one face in relief andrepresents the example of a printing plate.

Here the surface of the reversed capital letter F is raised in cameoabove the surface of the plate to form the actual printing surface, theletter being an integral part of the whole piece of say copper metal.

The first step in the process of duplication is to produce a matrix ormold pattern from the original object, using the original as a masterpattern.

This I accomplish by first, selection of the proper material for thematrix, second, heating the material to the proper teniperature, andlastly. forming the matrix by a direct impression therein of theoriginal.

The material required for the matrix must be of substantially lowermelting point than that of the original, and depending upon the hardnessand thermal properties of the original I have successfully used numerousof the non-ferrous alloys. In this particular illustration, an aluminumbase alloy might be employed. 7

The material chosen, before and during the time when the impression bythe original is being taken, is subjected to a continuous heating, whichmay be to the point of annealing, or even beyond to a somewhat plasticcondition. or therebetween, according to the state of malleability orductility at which the matrix material is desired, and depending alsosomewhat upon the depth and dimensions of the impression desired. It iswell known in metallurgy that viscosity in a non-ferrous metal or alloyis generally speaking a function of its temperature. Consequently insome cases a means of close heat control must be provided, and I haveaccomplished this by placing on the bed 5 (Fig. 1) of the press used,between the working face 6 of the bed and the matrix or copy material,an electric heating element as shown symbolically at 7 in the presentinstance, of smooth flat upper surface to contact thermally with thecopy material, and controlled by the thermo electric unit as showndiagrammatically at 9.

After the proper temperature has been attained, the impression is madeby forcing the original down upon the heated blank matrix or copymaterial, and maintaining the contact at the, proper pressure for aperiod of from a few seconds to about one minute, depending here againupon the materials, temperatures. and depth of impression. lhe type ofpress illustrated produces a short dwell in the contact at maximumpressure, but I have found it desirable in some cases to increase thedwell. which is easily done by temporarily slowing or stopping therotation of the pinion 10 at the proper time as required. or mayobviously be obtained automatically by proper alteration in the designof the cam 11.

Having in this manner produced from the cameo original 2, the intagliomatrix 3, an exact duplicate in form except of course the converse inworking surface, the next step is to produce from thematrix, as apattern or mold, the desired duplicate. This I accomplish in exactly thesame manner as the matrix was produced, except that a material of stilllower melting point is selected, as for example an alloy of lead base,and obviously the result (Fig. 4) of this step, being the com'erse ofthe intaglio matrix, is identical in its working surface with theoriginal.

It has been found that the duplicate thus obtained is far beyond theproduct of any process employed heretofore, in faithfulness ofreproduction. Not only are the surface dimensions of the duplicate thoseof the original. and the process completed without shrinkage, expansionor warping of either the matrix or duplicate; but also the minutestdetails of surface finish are reproduced with such great fidelity thateven a highly polished surface in the original appears with an equalpolish in the duplicate.

While I have illustrated and described by way of example an applicationof my invention more readily adapted to the printing industry, I do notwish to limit myself thereto, since my invention is equally useful inany instance where a like reproduction of particularly great accuracyupon one surface is acquired. Nor is my process to be construed aslimited in application to the reproduction of a single surface. By theinsertion of a second mold or pattern of sufficient heat resistant andconductive qualities between the heating element and the copy material,both sides of the product may be finished in the same operation: andlikewise by the use of matrix molds of generally concave faces, aproduct finished all over may be obtained.

As to specific metals used; my process may be applied to any metal whereI can utilize a pattern, mold or die of substantially higher meltingpoint and of sufficient hardness to withstand the requisite pressure,and I have been able to operate with ease on metals of: lead-base,tin-base, zinc-base,

aluminum-base, copper-base, silver-base and goldbase. In fact, in casesI have been able by application of more pressure and less heat. to usemetal of the same base, notably aluminum, for both pattern material andcopy material provided the material of the pattern was of either astronger alloy or harder temper. In this connection I have beenparticularly successful in the use of various compositions of thewrought light;- hard alloy of aluminum known to the trade as duralumin,the principal (onstituents of which in addition to aluminum, are between3% and 5% of copper and less than one per cent each of magnesium,silicon, manganese and iron. It is to be understood, however, that I donot Wish to limit myself to the use of non-ferrous metals, but obviouslyfor example a steel original would be thoroughly serviceable, and Icontemplate forming of ferrous alloys by my process, as well as thosealready designated.

I have also been able to employ in my process, copy material. alreadypolished and electro-plated with copper, brass and nickel, resulting ingreat econon'iy in obtaining a finished surface upon the completedproduct.

In my process a great advantage results from the application of the highpressure required in compressing the heated copy material, in that bythis means a greater densityis obtained in the product than that of themateral, and the tendency is obviously to eliminate air holes and reducethe pores within the metal itself as well as merely upon its surfaces.Moreover my process does not leave the metal in the product in a stateof strain. as would be the case in a cold working process.

An advantage of heating the copy material directly upon the press is thesaving of labor, time and thermal eflicency by obviating such apreliminary step as separate annealing.

A. still further advantage of my process is that of turning out theproduct of the press at a sufiiciently high temperature to allow of theimmediate application of some desired heat treating process.

Having thus illustrated and described my invention. what I claim is:

l. The process of metal working consisting in raising the temperature ofa piece of metal sufficiently to materially reduce its resistance tochange in form, subjecting the said piece to a gradually increasingpressure by a form changing tool, and maintaining the temperature of thesaid piece and the pressure thereon at maximum value an intervalsufticient to allow the said piece to completely conform in contour withthat of the said tool, but removing the said tool before it is itselfaffected in form.

2. The process of metal working consisting in raising the temperature ofa piece of metal sufficiently to materially reduce its resistance tochange. in form, subjecting the said piece to a gradually inereasingpressure by a form (n-ang ing tool of substantially similar rompmitioii.and maintaining the temperature of the said pieee and the pressurethereon at maximum value an interval suflieieut to allow the said pieeeto completely eou't'orm in eontour with that of the said tool. butremoving the said tool before it is itself atteeted in form.

3. A method of metal Working con1prising raisng the temperature of apiece of metal by Contact with a press bed member 15 sufficiently tomaterially reduce its resistance to change in form, subjecting the pieceto a gradually inereasing pressure by a Form ehan zing tool mounted inthe press, and maintaining the temperature of the pieee through saideontaet, and said pressure thereon, an inter 'al suflieient to allow thepieee to ('OIl'fOl'Ill in contour with that of said tool. butwithdrawing the tool before it is itself affected in form Signed by me,this 6th da of January, 1925.

JAMES ROSENBERG.

